“数组类型的方法未定义”是什么意思？答案

【问题标题】：What does "The method is undefined for the type Arrays" mean?“数组类型的方法未定义”是什么意思？
【发布时间】：2022-01-07 06:46:45
【问题描述】：

我正在尝试制作一个购物车程序，只使用数组。（不是数组列表）但是，我的“addItem”方法有错误，它说

方法 addItem(int[], int) 未为类型数组定义
方法 addItem(String[], String) 未定义数组类型

方法 addItem(double[], double) 对于 Scanner* 类型未定义
而且我不知道如何调试这个..有人可以帮我吗？（我还没有完成所有的菜单 - 开关/机箱。只想先完成“添加项目”）

导入 java.util.Arrays; 导入 java.util.Scanner;

公共类 A_retail {

  public static void main(String[] args) 
  {
      Scanner myinput = new Scanner(System.in);
      int total;
      int quantity;
      String name = null;
      double price = 0;
      String option;


      System.out.println("How many kinds of items do you have in total?");
      total = myinput.nextInt();

      int[] Quantity = new int[total];
      String[] Name = new String[total];
      double[] Price = new double[total];


      for (int i = 0; i<total; i++)
      {
          System.out.println("Please type the quantity of your item(s) (ex : If you have 2 shirts, please type 2));   
          Quantity[i] = myinput.nextInt();

          System.out.println("Please type the name of your item(s)");
          Name[i] = myinput.next();

          System.out.println("Please type the price of your item(s)");
          Price[i] = myinput.nextDouble();            
      }



      System.out.println("Please choose one option below \n1) Add item(s) \n2) Remove item(s) \n3) View Cart \n4) Checkout \n5) Exit");
      option = myinput.next();

      switch(option)
      {
      case "1" , "Add item(s)": 
          System.out.println("How many items do you want to add?");
          int add = myinput.nextInt();

          for(int i=0; i<add; i++)
          {
              System.out.print("Please type the quantity of your item(s)");
              quantity = myinput.nextInt();
              Quantity = Arrays.addItem(Quantity, quantity); //error in addItem


              System.out.print("Please type the name of your item(s)");
              name = myinput.next();
              Name = Arrays.addItem(Name, name); //error in addItem

              System.out.print("Please type the price of your item(s)");
              price = myinput.nextDouble();
              Price = myinput.addItem(Price, price); //error in addItem               
          }

          break;
      }


  }//end item


   public static int[] addItem(int[] array, int item)
     {
             int [] newArray = new int [array.length + 1];
             for (int i = 0; i<array.length; i++)
             {
                     newArray[i] = array[i];
             }
             newArray[newArray.length-1] = item;
             return newArray;
     }//end addItem

   public static String[] addItem(String[] array, String item)
     {
             String [] newArray = new String [array.length + 1];
             for (int i = 0; i<array.length; i++)
             {
                     newArray[i] = array[i];
             }
             newArray[newArray.length-1] = item;
             return newArray;
     }//end addItem


    public static double[] addItem(double[] array, double item)
    {
            double [] newArray = new double [array.length + 1];
            for (int i = 0; i<array.length; i++)
            {
                    newArray[i] = array[i];
            }
            newArray[newArray.length-1] = item;
            return newArray;
    }//end addItem

}//结束类

【问题讨论】：

它的字面意思就是：数组中不存在具有该签名的方法
通过 addItem(..., ...) 调用它们，而不使用Something。在前面。

标签： java arrays methods

【解决方案1】：

Quantity = Arrays.addItem(Quantity, quantity);

您正在使用 Arrays 类的 addItem 方法

 Scanner myinput = new Scanner(System.in);

 ...

 Price = myinput.addItem(Price, price);

您正在使用 Scanner 类的 addItem 方法

您没有使用您在 A_retail 类中声明的 addItem 方法

试试这个

Quantity = addItem(Quantity, quantity);
Name = addItem(Name, name);
Price = addItem(Price, price);

【讨论】：